Understanding Low-E Coatings

Transcription

1 Understanding Low-E Coatings CORPORATIVO LEGARIA ARCHITECT: ZVA ARQUITECTOS

2 Understanding Low-E Coatings Best Practices Vitro Architectural Glass is a registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-aia members are available upon successful completion of this course. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing or dealing in any material or product. Questions related to specific materials, methods and services will be addressed at the conclusion of this presentation.

3 Understanding Low-E Coatings Copyrighted Materials This presentation is protected by U.S. and international copyright laws. Reproduction, distribution, display or use of this presentation without written consent of the sponsor is prohibited Vitro Architectural Glass.

4 Understanding Low-E Coatings Learning Objectives At the conclusion of this presentation, you will understand: The solar energy spectrum and common glass performance measures The manufacturing processes for pyrolytic and magnetron sputter vacuum deposition (MSVD) low-e coatings How passive and solar control low-e coatings differ and impact glass performance measures Commercial energy usage and how low-e coatings can improve energy efficiency and earn LEED credit contributions FRONTRUNNER SYSTEMS ARCHITECT: EKASH ASSOCIATES

5 Understanding Low-E Coatings TOWER AT PNC PLAZA ARCHITECT: GENSLER NEMOURS/ALFRED I. DUPONT HOSPITAL FOR CHILDREN ARCHITECT: FKP ARCHITECTS BILL & MELINDA GATES FOUNDATION ARCHITECT: NBBJ UPMC EAST ARCHITECT: BBH DESIGN SAN FRANCISCO PUBLIC UTILITIES COMMISSION ARCHITECT: KMD ARCHITECTS

6 Understanding Low-E Coatings CHERRY STREET PLAZA ARCHITECT: GLENN WELLS ARCHITECT The Solar Energy Spectrum

7 The Solar Energy Spectrum

8 The Solar Energy Spectrum Short-Wave and Long-Wave Energy

9 The Solar Energy Spectrum Benefits of Energy-Efficient Glass Low infrared heat gain/transfer High natural visible light transmittance Less artificial lighting Reduction of long-wave heat gain/loss Increased comfort/productivity Results Overall reduction in energy usage

10 The Solar Energy Spectrum Understanding Emissivity The ratio of the thermal energy radiated from a material's surface to the thermal energy radiated from a blackbody (a perfect emitter), at the same temperature and wavelength, under the same conditions. Thermal heat that is not radiated away is either absorbed or transmitted through the glass. The lower an object s emissivity, the better it is at reflecting away heat. Emissivity works in all seasons and in all climates, always working to slow the transfer of heat. In cold seasons or climates, it reflects heat back into the interior of the building; in warm seasons or climates, it reflects heat back to the outside of the building. Reduced emissivity improves a window s insulating properties. Uncoated clear glass has an emissivity of 0.84 while a solar control low-e glass might have an emissivity as low as All uncoated glasses have the same emissivity. The addition of a well-engineered low-e coating reduces the emissivity and increases the reflectance of thermal energy. Low-e coatings do not necessarily increase the visible reflectance of the glass and can actually be less visibly reflective than uncoated clear glass.

11 The Solar Energy Spectrum Thermos Illustration Silver lining reflects the temperature of the drink it contains back in. Temperature is maintained because of the constant reflection that occurs. Air space provides additional benefits. Low-e glass is composed of extremely thin layers of silver. The same theory applies.

12 Understanding Low-E Coatings ORTHOPEDIC CENTER AT LANCASTER GENERAL HOSPITAL ARCHITECT: IKM INCORPORATED Passive and Solar Control Low-E Coatings

13 Passive and Solar Control Low-E Coatings Types of Coated Glass Low-E Glass Solar Control Low-E: Blocks solar radiation to reduce cooling costs. Higher-performing glasses are applied or produced by a magnetron sputtered vacuum deposition (or MSVD) soft coat process. Passive Low-E: Transmits solar radiation for passive heating applications. Reduces heating costs. Applied on products by a pyrolytic or MSVD soft coat process. Non-Low-E Glass Tinted Glass Reflective Glass Anti-Reflective Glass Shower Glass BILL AND MELINDA GATES FOUNDATION ARCHITECT: NBBJ

14 Passive and Solar Control Low-E Coatings The Float Glass Process

15 Passive and Solar Control Low-E Coatings CVD Coating (or Hard Coat ) Process

16 Passive and Solar Control Low-E Coatings CVD Coating (or Hard Coat ) Process On-line process where the coating is applied in the bath Stands up very well to further processing and fabrication Has an unlimited shelf life Limited ability to achieve high-performance solar control levels BROOKHAVEN NATIONAL LABS ARCHITECT: H.D.R. ARCHITECTURE, INC., OF ALEXANDRIA, VIRGINIA

17 Passive and Solar Control Low-E Coatings Sprayed-On Coatings (Spray Pyrolysis)

18 Passive and Solar Control Low-E Coatings Sprayed-On Coatings (Spray Pyrolysis) Application is considered an on-line process. Pyrolitic coatings are sprayed onto hot glass just after it exits the tin bath. Liquid suspension of various metal oxides reacts with surface, forming bonded and durable coating. May impart color to the substrate glass. Increases reflectivity while reducing light transmission through glass.

19 Passive and Solar Control Low-E Coatings MSVD Coating Process

20 Passive and Solar Control Low-E Coatings MSVD Coating Process Considered an off-line coating process. Total thickness of low-e coating is 150 nanometers. Applied to pre-cut glass in vacuum chamber at room temperature. Most solar control low-e glasses are MSVD. Depending on materials used, most should be sealed in an IGU or laminated. Enables lower emissivity and superior solar control performance. BANK OF AMERICA ARCHITECT: COOK+FOX ARCHITECTS LLP

21 Passive and Solar Control Low-E Coatings Insulating Glass Units (IGUs) Double-Pane IGU Four potential coating surfaces: Each glass surface in the IGU is numbered sequentially from the building exterior to the building interior. The first (#1) surface faces outdoors. The second (#2) and third (#3) surfaces face each other inside the IGU and are separated by an air space. In a dual-pane IGU, the fourth (#4) surface faces directly indoors; in a triple-glazed IGU the sixth (#6) surface faces directly indoors. Triple-Pane IGU The #5 surface in a triple-glazed IGU is the outermost surface of the room-side lite.

22 Passive and Solar Control Low-E Coatings Defining Your Low-E Coating Strategy Factors that may influence your low-e coating selection and placement strategy include: Heating or Cooling dominated climate Energy performance Building codes Project HVAC requirements Aesthetic objectives Site characteristics Additional design factors

23 Passive and Solar Control Low-E Coatings Double-Pane Solar Control Low-E Coating Placement Strategy Double-Pane IGU Apply solar control low-e coating to #2 surface of the IGU to maximize solar control performance. A second low-e coating (engineered for interior surface ) can be placed on surface #4 to optimize insulating performance. Only one low-e coating should be in an airspace for best performance.

24 Passive and Solar Control Low-E Coatings Triple-Pane Solar Control Low-E Coating Placement Strategy Triple-Pane IGU Apply a solar control low-e coating to the #2 surface and a second low-e coating to the #4 surface of the IGU to optimize solar control performance. Placing a third low-e coating engineered for interior surface (surface #6) of a triple-pane IGU will further enhance insulating performance.

25 Passive and Solar Control Low-E Coatings Passive Low-E Coatings Placement Strategy Unlike solar control low-e coatings, passive low-e coatings allow some of the sun s short-wave infrared energy to pass through and help heat building interiors.

26 Passive and Solar Control Low-E Coatings Double-Pane Passive Low-E Coatings Double-Pane IGU Apply passive low-e coatings to the surface of the innermost lite of glass, which are the #3 or #4 surfaces. The further away from the sun a passive low-e coating is placed, the more solar heat will be transmitted into the building.

27 Passive and Solar Control Low-E Coatings Triple-Pane Passive Low-E Coatings Triple-Pane IGU For optimal performance, place the low-e coating on surface #5. For additional insulating performance, the low-e coating can be moved to surface #4 and a second low-e coating engineered for interior surface can be added to surface #6. Marginally improve insulating performance by adding a second passive low-e coating to surface #3.

28 Passive & Solar Control Low-E Coatings Jumbo Glass Specify even larger expanses of low-e glass Most common sizes: 130" x 204" 130" x 236" Available on various substrates and at different thicknesses Considerations before specifying Impact on fabrication-installation chain Increased glass thickness to meet wind load requirements Specialized processing equipment, such as tempering ovens, and special handling equipment to account for added weight and size Not all fabricators have these capabilities

29 Understanding Low-E Coatings NEMOURS/ALFRED I. DUPONT HOSPITAL FOR CHILDREN ARCHITECT: FKP ARCHITECTS, HOUSTON Definitions & Comparisons of Glass Performance Measures

30 Definitions & Comparisons of Glass Performance Measures Short-Wave and Long-Wave Energy

31 Definitions & Comparisons of Glass Performance Measures Important Measurements There are four important measurements of glass performance. They are: Visible light transmittance (VLT) Solar heat gain coefficient (SHGC) Winter nighttime u-value Light to solar gain (LSG) FRONTRUNNER SYSTEMS ARCHITECT: EKASH ASSOCIATES

32 Definitions & Comparisons of Glass Performance Measures Coated Glass Terms U-Value: A measure of the insulating characteristics of the glass or how much heat loss it allows. U-values generally range from 0.2 (very little heat loss) to 1.2 (high heat loss). Visible Light Transmittance (VLT): A measure of how much light passes through a window. VLTs range from 0 (no light) to 1 (all light). Solar Heat Gain Coefficient (SHGC): Measures how well a window blocks the heat from sunlight. SHGC is the fraction of solar radiation transmitted through a window or skylight, as well as the amount that is absorbed by the glass and reradiated to the interior. SHGC is expressed as a decimal between 0 and 1. The lower a window's SHGC, the less solar heat it transmits and the greater its shading ability. Light to Solar Gain (LSG): Measures the ratio of visible light to solar heat gain (LSG = VLT SHGC).

33 Definitions & Comparisons of Glass Performance Measures Visible Light Transmittance (VLT)

34 Definitions & Comparisons of Glass Performance Measures Solar Heat Gain Coefficient (SHGC)

35 Definitions & Comparisons of Glass Performance Measures Additional Ways to Reduce Heat Gain Darker glass/multiple glass types Overhangs Interior shading devices Switchable technologies Ceramic frit White laminate

36 Definitions & Comparisons of Glass Performance Measures Winter Nighttime U-Value

37 Definitions & Comparisons of Glass Performance Measures Ways to Reduce U-Values & Improve Insulating Performance Utilize low-e coatings Use double-or triple-glazing Optimize gas cavity Use a noble gas (Argon or Krypton) fill Specify warm-edge spacers Apply low-e coatings within air cavity and to interior surfaces

38 Definitions & Comparisons of Glass Performance Measures Light to Solar Gain (LSG)

39 Definitions & Comparisons of Glass Performance Measures Benefits of Double- and Triple- Glazing Double-glazing Energy efficient Thermal insulation benefit Triple-glazing More surfaces available for additional low-e coatings More energy efficient Thermal insulation benefit Acoustic performance

40 Definitions & Comparisons of Glass Performance Measures Optimizing Glass Cavity Insulating glass units, or IGUs, are designed to keep buildings warmer in the winter and cooler in the summer. ½" is the optimal cavity size for air-filled units.

41 Definitions & Comparisons of Glass Performance Measures Using a Noble Gas (Argon or Krypton) Performance can be improved by filling the space between the two lites with a noble gas, such as argon or krypton. 90% argon gas-fill insulating value can be improved by up to 16%. Krypton can improve the insulating value in a low-e IGU by up to 27%.

42 Definitions & Comparisons of Glass Performance Measures Specifying Warm-Edge Spacers Create an effective thermal barrier at the edge of the IGU to help reduce heat loss. Can strengthen the glazing system better retain insulating gases.

43 How Low-E Coatings Improve Energy Efficiency Key Glass Performance Measures (in 1-inch IGU + Clear Glass) Low-e, ½" airspace, ¼" clear U-Value VLT SHGC Clear (Uncoated) % 0.70 Passive Low-E % 0.60 Double-Silver Solar Control Low-E (High VLT/Low Reflectance) Triple-Silver Solar Control Low-E (High VLT/Low Reflectance) Quad-Silver Solar Control Low-E (High VLT/Low Reflectance) % % % 0.23 *Specific manufacturers values may vary slightly

44 Definitions & Comparisons of Glass Performance Measures Tradeoffs Between VLT and SHGC for Coated Glass

45 Definitions & Comparisons of Glass Performance Measures Tradeoffs Between VLT and SHGC for Tinted Glass

46 Understanding Low-E Coatings SHANGRI LA BOTANICAL GARDENS AND NATURE CENTER ARCHITECT: LAKE FLATO ARCHITECTS How Low-E Coatings Improve Energy Efficiency

47 How Low-E Coatings Improve Energy Efficiency Energy and Environmental Performance for Glazing Low-e, ½" airspace, ¼" clear U-Value VLT SHGC Clear (Uncoated) % 0.70 Passive Low-E % 0.60 Double-Silver Solar Control Low-E (High VLT/Low Reflectance) Triple-Silver Solar Control Low-E (High VLT/Low Reflectance) Quad-Silver Solar Control Low-E (High VLT/Low Reflectance) % % % 0.23 *Specific manufacturers values may vary slightly

48 How Low-E Coatings Improve Energy Efficiency HVAC, Ventilation and Artificial Lighting 61% of a building s energy use Higher-performing low-e glasses quickly recoup upfront investment Commercial Facility Primary Energy Use Splits Water Heating, 7% Refrigeration, 4% Computers, 4% Cooking, 2% Cooling, Ventilation & Lighting, 61% Other, 14% Space Heating, 13% U.S. DOE, Office of Energy Efficiency and Renewable Energy (2012) 2011 Buildings Energy Data Book. Electronics, 8%

49 How Low-E Coatings Improve Energy Efficiency Commercial Electricity Prices Source: U.S. Energy Information Administration, Annual Energy Review 2015

50 How Low-E Coatings Improve Energy Efficiency Potential Impact of Energy-Efficient Glazing Most buildings in the country are not clad with the most efficient glass available. Commercial buildings consumed 19% of all energy in the U.S. in There are approximately 5.6 million commercial buildings comprising 87 billion square feet of built environment in the U.S. 2 By 2035 that figure is expected to climb to 103 billion square feet. 3 If this new development incorporates the most efficient glass technology available, significant upfront and long-term savings will result. 1 U.S. DOE, Energy Information Administration (EIA) (2012) Annual Energy Review EIA (2016) 2012 Commercial Buildings Energy Consumption Survey. 3 EIA (2012) Annual Energy Outlook MCGILL UNIVERSITY, SCHULICH SCHOOL OF MUSIC ARCHITECT: MENKÈS SHOONER DAGENAIS LETOURNEUX; SAUCIER + PERROTTE ARCHITECTES

51 How Low-E Coatings Improve Energy Efficiency IECC : Mapping Performance Needs IECC prescribes energy performance requirements. Eight U.S. regions with patterns of annual heating/cooling demands. Glass and window products can be specified based upon their fit for the region in which they will be installed.

52 How Low-E Coatings Improve Energy Efficiency Commercial Energy Code Status As of November 2017

53 How Low-E Coatings Improve Energy Efficiency Increasing Stringency ASHRAE 90.1

54 How Low-E Coatings Improve Energy Efficiency Increased Stringency for Windows U-factor has seen steady decrease. Example in zone 5 (Chicago): For ASHRAE 90.1, 7%-9% reduction from 2010 to 2013 and then another 8%-10% reduction from 2013 to IECC made the jump all at once 16%-18% reduction from 2009 to 2012, then stayed same for SHGC has been more stable. From : 0.25 in south, higher in central and northern zones (0.36 to 0.45). Credit given for exterior shading from overhangs, sun shades includes additional requirements encouraging proper building orientation, and lower SHGC or shading on west and east. IMPORTANT: Code requirements are for the whole assembly including both the framing and glazing, not just center-of-glass only. Must be based upon NFRC technical procedures, but does not have to be full NFRC certification, except in certain locations, such as California and Seattle.

55 How Low-E Coatings Improve Energy Efficiency Energy and Environmental Performance The U.S. Green Building Council Promote energy efficiency and sustainable design LEED (Leadership in Energy and Environmental Design) program LEED credits influenced by glass selection: Energy and Atmosphere (Energy Savings) 18 points available Cradle to Cradle Certification, MBDC Environmental Product Declarations (EPD)

56 How Low-E Coatings Improve Energy Efficiency LEED Overview Established by the USGBC in 1998 Premier benchmark for sustainable design New construction after Nov. 1, 2016 requires LEED v4 Older projects may be grandfathered to previous versions Must collect at least 40 points for minimum level of LEED Certified Silver Gold Platinum

57 How Low-E Coatings Improve Energy Efficiency LEED Credit Categories Where Glass Can Contribute Points can be earned across numerous credit categories: Integrative Process 1 point Sustainable Sites 2 points Material & Resources 2 points Building Product Disclosure & Optimization 1 point Indoor Environmental Quality 1 point Innovation 6 points Energy & Atmosphere 18 points available

58 How Low-E Coatings Improve Energy Efficiency Energy & Atmosphere (EA) Credit: Optimize Energy Performance 18 points available Intent: To achieve increasing levels of energy performance beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use. Applicable Requirements: Whole Building Energy Simulation (Option 1) 18 points available Prescriptive compliance: ASHRAE Advanced Energy Design Guide (Option 2) 1 point available

59 Understanding Low-E Coatings BUILDING: BAKERY SQUARE ARCHITECT: ASTORINO Low-E Glass Case Studies

60 Understanding Low-E Coatings Nemours/duPont Hospital for Children Location: Wilmington, Delaware Architect: FKP Architects Certification: LEED Silver Strategy: Solar Control Low-E Products: Double-silver MSVD solar control low-e glass with aqua-blue tint Triple-silver MSVD solar control low-e glass

61 Understanding Low-E Coatings The Tower at PNC Plaza Location: Pittsburgh, Pennsylvania Architect: Gensler Certification: LEED Platinum Strategy: Double-wall design with passive low-e glass Products: MSVD passive low-e on low-iron glass

62 Understanding Low-E Coatings The Terry Thomas Location: Seattle, Washington Architect: Weber Thompson Certification: LEED Gold (Core and Shell) / LEED Platinum (Commercial Interior) Strategy: Solar Control Low-E Products: Triple-silver MSVD solar control low-e glass

63 How Low-E Coatings Improve Building Performance This concludes the continuing education portion of the course. Here is a quick review of the learning objectives we discussed today: The solar energy spectrum and common glass performance measures The manufacturing processes for pyrolytic and magnetron sputter vacuum deposition (MSVD) low-e coatings How passive and solar control low-e coatings differ and impact glass performance measures Commercial energy usage and how low-e coatings can improve energy efficiency and achieve LEED credits

64 Features & Benefits of Vitro Architectural Glass Thank You For more information visit vitroglazings.com or call (1.855.VTRO.GLS) Vitro Architectural Glass is an industry leader in manufacturing architectural glass and was the first to introduce triple-silver MSVD solar-control Low-E glass. For more information on the study and its results you can contact Vitro by visiting vitroglazings.com, or by calling VTRO-GLS ( ).